(1) Field of the Invention
This invention relates to pumping viscous, edible material with a fluid motor operated pump having a rotating plug valve for opening and closing the intake and outlet port of the pump.
(2) Description of the Prior Art
In the food industries, it is often desirable to pump viscous, edible materials, for example, moving of dough, soup, batter or the like. It has been found desirable to do this with reciprocating pumps and using a rotating plug valve to connect the pump cylinder to its intake and outlet port. Examples of such pumps are MOJONNIER ET AL U.S. Pat. No. 1,794,388, KERR U.S. Pat. No. 3,096,914 and AUSTIN ET AL U.S. Pat. No. 3,385,479.
Before this application was prepared, applicant caused a search to be made in the U.S. Patent and Trademark Offices. In addition to the above patents, the following patents were reported:
JEFFREY U.S. Pat. No. 1,719,806 PA1 LOOMIS U.S. Pat. No. 2,702,409 PA1 NORMAN U.S. Pat. No. 2,896,257 PA1 KELLEY U.S. Pat. No. 3,379,143 PA1 McARTHUR U.S. Pat. No. 4,170,253 PA1 COLOSIMO U.S. Pat. No. 4,293,979 PA1 PERSSON U.S. Pat. No. 4,302,173
These patents do not appear pertinent to the applicant. They are called to the attention of the Examiner since the applicant believes they would be of interest to the Examiner inasmuch as an experienced searcher reported them upon the search.
When a pump is used to pump food it is necessary at the end of each days work, that the pump be cleaned. The more completely the pump is disassembled, the better it can be cleaned. Although this is a recognized objective for food handling equipment, the prior art devices have not always had pumps which were readily and easily disassembled.
In pumping a viscous material, difficulty is experienced with the seals at the pump piston and with the seals of the valves. More difficulty is experienced on the suction stroke than on the pressure stroke. When a charge of viscous material is being drawn into the pump on the suction stroke, problems exist with the air being sucked into the cylinder. This reduces the efficiency of the pump drastically. This makes the design of a pump for viscous, edible material even more difficult. Not only must the seals withstand a vacuum, the pump must be disassembled readily.